TM 9-2320-280-20-1REFERENCE INFORMATIONWatch the fuel pump pressure while slowlyaccelerating the angina from idle to maximum speed.The pressure should always be greater than zero. Ifpressure, check to be sure it is still above zero evenduring maximum acceleration (maximum enginepower). You can use STE/ICE test 24 with controlfunction 02 (minimum).NOTERapidly accelerating the engine with the transmissionin neutral doesn't work for this engine because thefuel supply cant increase as fast as the engine canaccelerate so you wont get good test results.Proper engine performance is dependentupon the availability of the correct fuelvolume to the injection pump.Pay attention to when the engine runs rough. If itruns rough only while warming up after a cold start itmay be a glowplug problem and you should run theGlowplug Circuit tests.Rough running may also be caused by air leaks in thefuel supply lines. Air in the fuel should purge itselfwhile idling. If rough running occurs after a period ofhigh speed or high power running but seems to goaway after idling, then look for air leaks in the fuelsupply lines and fittings. if rough running occurs whiledriving but idles ok, check the fuel return check valvefor any malfunctions (refer to para. 3-35).NOTETry to adjust the engine idle speed byturning the idle speed screw (refer to para 3-44).Continue testing if you can adjust thespeed properly. If you cannot, notifyDS maintenance.Engine must be at normal operating temperaturewhen making speed checks. Air fitter must be inplace and all accessories (lights, heater fan, etc...)must be turned off.This engine has a min-max governor which controlsengine speed at both idle and full throttle.FUEL SYSTEM2-99